The problem with the obsidian shards was that while it was extremely sharp, it chiped away at a fast speed. Obsidian blunt weapons were the more common ones. Not anywhere near the medieval times anyway.
While in the dark ages there were spiked gauntlets just as other armor pieces they were never made to be a weapon by themselves. Just an additional damage inflicting surface. All of them were individual modifications and it was never wide spread. In the game a gauntlet could be a weapon by itself. A 2h weapon since it would take up both hands. Same type could be a claw or a bladed one. It is questionable to fit in or even be useful, but again it only depends on how far the devs gonna go with it. With a will you can make even a gauntlet an unique type weapon.
